Miniature electric motor



1966 J. KONIJNENBERG ETAL 3234414 MINIATURE ELECTRIC MOTOR Filed March 19, 1963 INVENTORS JOHAN KONIJNENBERG HIDDE VAN DER BIJL United States Patent MINIATURE ELECTRIC MOTOR Johan Konijnenberg and Hidde van der Bijl, Drachten,

Netherlands, assignors to N0itl1 American Philips Company, Inc. New York, N.Y., a corporation of Delaware Filed Mar. 19, 1963, Ser. No. 266,260 Claims priority, application Netherlands, Mar. 26, 1962,

276,428 4 Claims. (Cl. 310-47) Ths invention relates to small electric motors of 10W power, particularly useful for articles of domestic use, dry-shaving apparatus and the like, and its object is to simplify and make the structure and the assembly of such machines less expensive.

In order that the invention may be readily carried into effect, it will now he descrihed in detail, hy way of example, with reference to the accompanying diagrammatic drawing, in which:

FIG. 1 is an end elevational view of a stator with two pole-pieces for an electric motor having a single shield shown in section. FIG. 1A is a side elevation of FIG. 1 with hoth shields and hearing carriers in place.

FIG. 2 showsa perspective of a metal shield of resilient material.

FIG. 3 shows a cylindrical shield of resilient material.

FIG. 4 shows the cylindrical shield of FIG 3 hut provided with a base or hottom wall and with a hearing carrier mounted in place.

FIG. 5 shows the manner of introducing the cylindrical shield of FIG. 4, hut without a hearing carrier, and into assemhly with the stator of FIG. 1.

FIG. 6 shows a different stator structure with the shields in place. FIG. 7 shows a perspective view of a shield.

Referring now to FIG. 1, the referenoe numeral 1 indicates a stator body having a winding 2 and pole-pieces 3 and 4. The pole-piece 3 is shown with a shield 5 in place and pole-piece 4 is without a shield. A shield 5 best seen in FIG. 2has a rectangular aperture 6 and is made of resilient material so that it can he bent into a slightly curved shape and attached onto a pole-piece hy sliding the pole face through aperture 6. The faces of each pole-piece is hevelled as at 7 and the corresponding edges 8 of the aperture 6 in the shield 5 are hevelled so that, after placing the shield on the stator pole, a dovetail-like connection between the pole-piece and the shield is established. The rotor shaft is journalled in hearing carriers 9 in the form of a stepped disc as shown in FIG. 4. The hearing carriers 9 are slid, one on each end and in between the stator shields 5 as indicated in FIG. 1A, whereby the structure of the stator is completed. With a suitahle choice of the various dimensions of the hearing carriers they are friction illed or clamped hetween the stator shields and the air-gap of the rotor relative to the shields is fully determined. Furthermore it is not necessary to provide self-adjusting hearings in the hearing carriers.

As an alternative, the two shields 5 may he united into a single sleeve shield 12 as shown in FIG. 3, which has an axial slot 13 and may he introduced into the stator 1 by a simple deformation. It is also possible to provide a cup-lke shield 12a with a closed end 14, as shown in FIGS. 4, 5 and 7. This base may then serve as a hearing carrier at one end so that only one hearing carrier 9 only is required at the other end (FIG. 4). In this case the axia l slot 15 extends through only part of the length of the sleeve, as shown in FIGS. 5 and 7. It has been found that the shield 12a may readily he placed in position hy compression in a direction at right angles to the gap adjacent the open end of said sleeve.

A variation of stator 16 is shown in FIG. 6 in which permanent magnets 17 carry pole-pieces 18, may he provided with shields of the type shown in FIG. 2 or a shield of the type seen in FIGS. 3 or 7. In 2111 these cases a stator is obtained which may he readily assemhled, while accurate tolerances need not be adhered to due to the great flexihility of the shields 12 and 12a and an air-gap between the rotorand the pole shields may thus he ohtained which has a uniform dimension.

What is claimed is:

1. A miniature electric motor having a rotor and rotor shaft projecting from each end thereof, comprising a generally U-shaped stator memher defining a pair of oppo-site pole-pieces, each said pole-piece having a pair of bevelled surfaces; elongated shield means of resilient metal having a radius of curvature suhstantially equal to the radius of curvature of the rotor for said rotor and an efective diameter greater than the diameter of said rotor, an aperture in each said shield means having a pair of hevelled surfaces corresponding with the hevelled surfaces of said pole-pieces for positioning said shield means concentric with said rotor and for fitting over said pole-pieces and connecting said shield means to said polepieces in a dovetail-like connection, and hearing carrier means connected with said shield means at each end thereof for providing a hearing support for the rotor adjacent each end of said rotor shaft.

2. A miniature electric motor according to claim 1 wherein said shield means comprise a pair of semi-circular plates.

3. A miniature e1ectric motor according to claim 1 wherein said shield means comprises a cylnder having an axial slot.

4. A miniature electric motor according to claim 1 wherein said shield means comprises a cylinder having a hottom wal] at one end and an open end, and an axial slot extending from said open end along a part of said cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,063,340 12/1936 Ruben --31046 2,438,621 3/1948 Schoeppel. 2,659,831 11/1953 Lautner 310 2,683830 7/1954 Staak 310-40X 2,939,024 5/1960 Mahuchi. s1ss,ss7 6/1964 Schatfan.

FOREIGN PATENTS 1,229368 3/1960 France.

MILTON 0. I-IIRSHFIELD, Primary Examiner. 

1. A MINIATURE ELECTRIC MOTOR HAVING A ROTOR AND ROTOR SHAFT PROJECTING FROM EACH END THEREOF, COMPRISING A GENERALLY U-SHAPED STATOR MEMBER DEFINING A PAIR OF OPPOSITE POLE-PIECES, EACH OF SAID POLE-PIECE HAVING A PAIR OF BEVELLED SURFACES; ELONGATED SHIELD MEANS OF RESILIENT METAL HAVING A RADIUS OF THE ROTOR FOR SAID ROTOR AND THE RADIUS OF CURVATURE OF THE ROTOR FOR SAID ROTOR AND AN EFFECTIVE DIAMETER GREATER THAN SAID SHIELD MEANS HAVING A ROTOR, AN APERTURE IN EACH OF SAID SHIELD MEANS HAVING A PAIR OF BEVELLED SURFACES CORRESPONDING WITH THE BEVELLED SURFACES OF SAID POLE-PIECES FOR POSITIONING SAID SHIELD MEANS CONCENTRIC WITH SAID ROTOR AND FOR FITTING OVER SAID POLE-PIECE AND CONNECTING SAID SHIELD MEANS TO SAID POLEPIECES IN A DOVETAIL-LIKE CONNECTION, AND BEARING CARRIER MEANS CONNECTED WITH SAID SHIELD MEANS AT EACH END THEREOF FOR PROVIDING A BEARING SUPPORTING FOR THE ROTOR ADJACENT EACH END OF SAID ROTOR SHAFT. 